|
Audio Asylum Thread Printer Get a view of an entire thread on one page |
For Sale Ads |
184.6.64.129
In Reply to: RE: Resistor dissipation Question posted by timp on September 15, 2012 at 20:58:19
Power equals Voltage times Current (in Amperes), Ohm's Law.I always make sure there is 2 to 1, rated versus dissipated, and I am MOST HAPPY when it is 4 to 1, rated versus dissipated, for long term reliability and fail-safe operation.
I ventilate my chassis on DIY builds, above and below power resistor bodies that dissipate a lot. I drill 3/8ths inch vent holes on 9/16ths inch centers, three in a row, for Mills MR-12 power resistors, looks "uptown".
Jeff Medwin
Edits: 09/15/12Follow Ups:
...... "Power equals Voltage times Current (in Amperes), Ohm's Law" is not Ohms law. Ohm's law: I=V/R more or less.
it's a combination of Joule's first law and Ohm's law, but all of those relationships between I, V, R, and P are commonly referred to as "based on Ohm's law..."
I ^2 R will give you the actual Pdiss in watts across the resistor.
or
Ohm's law: I=V/R , as Steve O pointed out.
Then x3 or x4 that result, for the resistor rating in watts for good sleep factor and longevity.
NI wirewounds run much hotter than inductive. Mills used to post the curves on their website prior to being bought out by Huntington.
The Dale RH AL. housed resistor(or any AL housed resistor) should have a "W" rating for mounted and not mounted. See how low the wattage rating drops when not properly heat sinked to a metal housing. Some x-fer grease helps.
Cheers,
W
Useful reference, on my wall....
Thanks Jeff!
Post a Followup:
FAQ |
Post a Message! |
Forgot Password? |
|
||||||||||||||
|
This post is made possible by the generous support of people like you and our sponsors: